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Reference Red Cell Serology / Obstetric Serology Tests and availability

Published on 14 October 2021

All samples referred to SNBTS for testing should be aligned to the appropriate testing pathway detailed below:

Pathway 1 ABO investigation and anomalies

Samples can be referred for investigation if anomalous results are obtained with routine grouping reagents. An extended serological investigation will be performed to investigate ABO grouping anomalies.

The genetics of ABO is complex, rendering ABO molecular typing by available methods unreliable. Where ABO anomalies cannot be resolved by serological technique, current guidance recommends that group O red cells are selected if transfusion is required. On occasion, where rare variants are suspected, individual cases may be referred onward to the International Blood Group Reference Laboratory (IBGRL) in Filton and may require further samples including saliva.

Pathway 2 RhD type confirmation

Samples sent for confirmation of D type due to a ≤2+ reaction with one or more anti-D reagents may undergo allele specific PCR for the detections of weak D types and variant D types, unless they meet exclusion criteria. This testing will be performed at the Glasgow RCI laboratory and should only be requested if the patient is under 18 years of age, of child bearing potential, or is likely to require chronic transfusion support. Otherwise, as per BSH guidelines, the group should be reported as Rh D positive. Samples should be sent to your regional transfusion centre for onward transport to Glasgow SNBTS if required.

Pathway 3 Antibody identification

The RCI laboratory will investigate samples with antibodies to high frequency antigens, complex mixtures of antibodies, warm and cold red cell autoantibodies. Straightforward individual antibodies and mixtures detectable with standard identification panels are not considered as reference samples and should be concluded at the local blood bank.

Samples should be sent to your regional transfusion centre for investigation in the first instance and may be referred on to Glasgow SNBTS if Red Cell Genotyping is required.

Pathway 4 Antibody quantification

RCI offers an antenatal reference service for women whose plasma contains irregular antibodies. The specificity of the antibody is determined or confirmed and the concentration is measured. If this is of clinical significance to the foetus, the antibody will be quantified (for anti-D, and c, this is performed at the Glasgow SNBTS site only) or titrated (anti-K and other clinically significant antibodies) and follow up tests performed as recommended by the BSH and RCOG guidelines.

With the exception of anti-D or anti-c antibodies should be titrated at the local blood bank. Samples should be sent to the SNBTS RCI laboratory if complex mixtures result in the lack of availability of appropriate cells to allow titrations to be performed or if quantification is required.

Pathway 5 Haemolytic transfusion reaction

Pre and post-transfusion samples should be sent for ABO typing, RhD grouping, DAT, antibody screen/identification and eluate where a possible haemolytic transfusion reaction has been confirmed and investigation has been requested by clinical haematology staff.

Pathway 6 Antenatal/renal titration

RCI laboratories can perform antenatal titrations for anti-K and other clinically significant antibodies. In accordance with BSH and RCOG guidelines, levels for anti-K should be titred every 4 weeks until 28 weeks’ gestation, then every 2 weeks until term (unless an IUT programme is instituted beforehand). Please refer to the Scottish Guidance on Management of Red Cell antibodies in Pregnancy document (2019) for further information.

With the exception of anti-D or anti-c antibodies should be titrated at the local blood bank. Samples should be sent to the SNBTS RCI laboratory if complex mixtures result in the lack of availability of appropriate cells to allow titrations to be performed or if quantification is required.

ABO titrations can be performed on request for renal transplant donors/recipients to ensure that plasmapheresis is reducing the levels of anti-A and anti-B present. This thereby reduces the risk of graft rejection. ABO titrations can be performed for allogeneic haematopoietic stem cell donors/recipients. Samples should be referred to your regional transfusion centre in the first instance, they will then be referred on to Edinburgh/Glasgow SNBTS as required.

Pathway 7 Monoclonal therapies

To support monoclonal therapies, SNBTS recommends pre-treatment testing be performed to confirm the ABO/RhD and extended phenotype; this supports the provision of blood if required. If the SNBTS laboratory is unable to obtain an extended phenotype by serological methods, genotyping can be performed.

Following the start of monoclonal therapies local blood banks are recommended to perform ABO/RhD and antibody screening by manual techniques due to the potential for carry over on automated platforms. If interference is observed samples can be sent to your regional SNBTS RCI laboratory for further testing. This service request will result in a cross charge to your hospital boards in line with the current Service Level Agreement (SLA) that is in place with SNBTS.

Blood Requirements

SNBTS must be informed prior to sending samples for crossmatch or urgent investigation. The urgency of the case must be discussed to ensure the request is prioritised appropriate to Clinical requirements.

It is important to provide details of special requirements for blood components; this will ensure that suitable components are available and prevent unnecessary delay in procurement of blood.

Test Availability

Read our policy on Referral of test requests

  • ABO Investigation and Anomalies: Aberdeen / Dundee / Edinburgh / Glasgow and Inverness
  • RhD Type Confirmation: Aberdeen / Dundee / Edinburgh / Glasgow and Inverness
  • Antibody Identification: Aberdeen / Dundee / Edinburgh / Glasgow and Inverness
  • Antibody Quantification: Glasgow only
  • Haemlytic Transfusion Reaction: Aberdeen / Dundee / Edinburgh / Glasgow and Inverness
  • Anenatal / Renal Titration: Aberdeen / Dundee / **Edinburgh / **Glasgow and Inverness
  • Monoclonal Therapies: Aberdeen / Dundee / Edinburgh / Glasgow and Inverness
  • Crossmatch: Aberdeen / Dundee / Edinburgh / Glasgow and Inverness

**Please note: Renal Titrations are performed in Edinburgh and Glasgow only.

Pathway and Sample Requirements

  • ABO Investigations / Anomalies: 10ml EDTA
  • RhD Type Confirmation: 10ml EDTA
  • Antibody Identification: 10ml EDTA
  • Antibody Quantification: 10ml EDTA
  • Antenatal / Renal Titration: 10ml EDTA
  • Monoclonal Therapies: 10ml EDTA
  • Crossmatch: 10ml EDTA
  • Haemolytic Transfusion Reaction:
    • 10ml EDTA Pre transfusion sample
    • 10ml EDTA Post transfusion sample
    • 7ml Clotted Post transfusion sample